If I have trouble with this oil pump again I am going to do the conversion. I had the switch turned of on the torsion while it was being worked on. When I picked up the car we still had to put in the oil pressure sending unit. I turned it on to level it out. Two of us were leaning on the front and got of the fender and bumper and the front end started to go up. I tried to get to the switch to turn it off but didn't make it. Now the back end is down and won't come up.

Update on my car....it's in my garage again. The mechanic came back early and was in the process of taking the pump apart and couldn't get the pressure relief value out. It was stuck. He finally got it out...inspected spring and shined the valve, put it back together and now it runs a little above the half way mark normal speed and a little below at idle. The only other thing is the rear in is down and the torsion is no running. It think he ran it beyond the stops. I know there is a way to correct that, but I can't remember. Thanks again for the help. The mechanic read all the posts and said he is learning more about the Packard's. (this is his first one)

Thanks for all the advice. The person working on the problem was called away on a emergency job and probably won't be able to work on in till after the holidays. I'm at the point now that if he can't find the problem I am going for to Olds option. I've relayed all the info to him and I'll wait to see what happens. Thanks again and I will let you know if he actually finds and corrects the problem.

We don't know which oil pump it is. It should be for the later 56's, the car is one of the last made (1260). The number on the casting is 6492430. This has a cap on the bottom of the relief value bore (as explained to me). Also it take two or three second to indicate oil pressure with the mechanical pressure gauge also. It's seem like when the engine is turned off all the oil is draining back into the back.

I had a major rebuild on my 56 Caribbean done. After the rebuild everything was fine, good oil pressure (middle of the gauge). After about 300 or 400 miles the pressure started to drop to 0 when the car was stopped and back up to normal when moving. Checked it with a mechanical gauge and I get the same readings. No lifter noise. It also takes a few seconds to for the gauge to move after the engine is started. The person working my the pump thinks is the problem is the relief valve. He noticed that when he turns the shaft backwards oil squirts out the vacumn vent (as explained to me my him)and he doesn't think that normal. Any thoughts? The oil pump was a new replacement.

Thanks for the replies! It was a 9/16. Last time I saw one was 1965 or so....didn't remember how it looked underneth. It was a bear getting out. Had to unhook a couple of things to get to it. I finally used one of those stubby wrenches and it worked good. Thanks again.....

Is there a special way to get the oil pressure sender out? My pressure is dipping down to zero when I stop my car and stop light ETC. I want to take a pressure check but have been unable to figure out a way to get the sender out. When the car is moving the pressure is between 11 and 1 o'clock. Thanks for any help....

Thanks for all the advise. I will print it all out and show it to my racecar mechanic. The distributor is orignal one. The block was the only thing my father had to change out. I found a list of pure gas (without enthanol). The highest octane rating was 93. I tried the tetraethyl before but it didn't seem to improve the performance. That might have be due to the really bad job the people that originally restore the engine. I will give it another try. I will also look up the info on the vitameter. Thanks again...Don

I have a Caribbean that had to have the engine rebuilt.
When they went to start it after the rebuild...it started squirting gas out of the bowl and the fuel fuel pump wasn't working. My mechanic said the the ethanol in the gas at up the rubber in the fuel pump and bowl. He also said because of the compression ratio I have to run an avgal mixture or I might mess up my pistons. Does anyone have problems with todays gas in their 374's and how do you cope with it? Thanks for any help on this. Don